Precision capacitance bridges such as the QuadTech 1615 and 1616 referred to earlier have ranges up to 1 μF at high accuracy. This range can be extended somewhat by using external standards, but the accuracy deteriorates rapidly as the capacitance is increased because of the inductance of the wiring and the leakage inductance of the ratio transformer used in the bridge. These bridges are three‑terminal; there is a guard but single connections are made to each end of the capacitor being measured. For good accuracy at higher values, four‑terminal (Kelvin) connections are needed to remove the effects of self inductance. Automatic short‑circuit zero corrections are a good way to remove the remaining effects of mutual inductance between leads.

The 1689 has these capabilities of four‑terminal connection and auto zeroing as well as extreme range and good accuracy. The normal range of the 1689 extends to 0,099999 F, but using its RATIO mode the display range can be extended (nominally) to 10,000 Farads! However, don't look for a capacitor of that value to measure, for even if one could be found, the 1689 would not be able to measure it. However it can measure 1 F with fairly good accuracy at 100 Hz even though its specifications might not indicate so. This is because the 1689 specifications assume that the zeroing calibrations, open and short, are made at 1 kHz only. If these are made at the frequency of measurement, the accuracy of extreme values depends mainly on the repeatability, which can be improved by averaging. For example, at 100 Hz the accuracy specification at 1 F is 120 %, but with a short‑circuit calibration at 100 Hz, accuracy is about 5 % for one measurement and 2 % if 10 measurements are averaged. And yes, there are standards of capacitance at such values, for example the QuadTech 1417 Capacitance Standard. There are special fixture considerations that improve the measurement accuracy of the 1689 by 5 to 1 at such values. More important are measurements on standards of lower values, between 1 μF and 1 F, again such as the 1417. The 1689 can measure these with good accuracy, usually better than required since these standards are less stable than lower valued ones, such as the QuadTech 1404 or 1409 Standard Capacitors.